I already know a good deal about Latin and the Romance languages but now I want to learn Germanic.Could someone recommend some good books that discuss the features of the Germanic languages and/or Proto-Germanic?
A newer book is Donald Ringe's A History of English: volume one treats Proto-Indo-European to Proto-Germanic, and volume two treats Proto-Germanic to Old English. The second volume's manuscript at least is still available on the internet, which is probably why Wikipedia/Wiktionary bases it's reconstruction of Proto-Germanic completely on Ringe. I also know of Lehmann's grammar, which has a section on syntax. For an introduction in the context of other IE. languages there's Routledge's The Indo-European Languages, but it's chapter on Germanic is quite short.